Download or read book Nonlinear and Chaotic Magnetization Dynamics in Single domain Nanoparticles and Exchange coupled Thin films written by Aaron Michael Ferona and published by . This book was released on 2018 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we study two fundamental issues in nonlinear magnetism: the nonlinear dynamics of nanoparticles and the nonlinear dynamics of exchange-coupled thin-films. The behavior of a uniformly magnetized domain of ellipsoidal shape subject to a static external field and oscillatory external driving field is analyzed near bifurcation events. The analysis includes the effects of both linear and circularly polarized driving fields and is performed using numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equation. Under a linearly polarized driving field, the LLG equation is a nonautonomous differential equation which can lead to complex magnetization motions, such as bistability, multi-periodic orbits, quasiperiodicity and chaos. Under a circular polarized driving field, the LLG equation can be written in autonomous form by transforming to the frame rotating with the driving field. The autonomous nature allows one to perform a fixed point analysis of the system for select demagnetization factors. Similarities and differences between the driven systems are highlighted through, bifurcation diagrams, phase portraits, basins of attraction and Lyapunov exponents. Magnetization switching, prolonged transients, quasiperiodicity, and chaos are observed with both linear and circularly polarized driving fields in the magnetic systems investigated. We also investigate the dynamics of exchange-coupled ferromagnetic films in the nonlinear limit and find a number of interesting features. These include the following: 1) A power-dependent localization of the magnetization oscillations; 2) A nonlinear mixing of the acoustic and optic modes in the antiferromagnetically coupled system leads to quasiperiodic and multi-periodic composite modes; 3) Ferromagnetic resonance experiments will show new absorption peaks (in the 20-50 GHz range) which have a rapid increase in strength with input power. As with the case of the uniformly magnetized domain, the results are calculated through linearization techniques and numerical solutions of the LLG equation. The nonlinear (and linear) behavior is illustrated through Poincare section bifurcation diagrams and power absorption curves.
Download or read book Handbook of Nanomagnetism written by Rosa A. Lukaszew and published by CRC Press. This book was released on 2015-10-06 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique handbook compiles and details cutting-edge research in nanomagnetism and its applications in spintronics, magnetoplasmonics, and nonlinear magneto-optics. Fundamental aspects of magnetism relevant to nanodevices and new spin-transfer torque random-access memory (STT-RAM), current-induced domain wall motion memory, and spin torque oscill
Download or read book Magnetization Dynamics at the Nanoscale in Nanoparticles and Thin Films written by Sergi Lendínez Escudero and published by . This book was released on 2015 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research in magnetic materials leads to new devices and technologies. As the technology progresses, the devices become smaller and this miniaturization allows more storage capacity and lower costs in the production of new technologies. As new and smaller materials are fabricated, new phenomena appear and thus new physics is needed to describe them. Nanomaterials meet characteristics of both the microscopic quantum world and the macroscopic classic world. This intermediate length scale is known as mesoscale. Nanomaterials can be obtained in a variety of forms, being nanoparticles and magnetic ultra-thin films some of the most used. These magnetic systems are very different in their composition: nanoparticles are grown with chemical reactions, and thin films are grown on a substrate by nanofabrication techniques such as sputtering or electron-beam evaporation. The magnetization might not be uniform in a magnetic thin film or in a large magnetic nanoparticle leading to the formation of magnetic domains. Magnetic domains are static structures that appear due to competition of the different magnetic energies and can be used to store and transport information. In all these systems, the magnetization dynamics gives rise to new behavior not visible in static measurements: quantum steps of the magnetization in molecular magnets; characteristic resonant frequencies that can be used to control the magnetic state of vortices; and formation of magnetic droplet solitons in thin films with perpendicular magnetic anisotropy. Understanding the dynamics of nanomaterials and the evolution of the magnetization is a key process to develop faster devices and technologies. The early studies of molecular magnets showed quantum effects at the macroscopic scale, which have allowed a better understanding of spin. Magnetic vortices have been proposed for multiple applications, from magnetic storage of information to cancer cell destruction. The recently discovered magnetic droplet soliton is also a very good candidate for technological applications due to the low current and magnetic field needed for its generation, and it is now a system with a growing interest in spintronics. In this dissertation we show some new dynamic phenomena. In the first part of the thesis we study systems that allow a macroscopic-spin model where spatial variations of magnetization are neglected. We develop a theory that sets the requirements for the observation of the rotational Doppler effect in a ferromagnetic system and we measure quantum effects in randomly oriented nanoparticles of a single-molecule magnet, which might be a good candidate for the observation of the Doppler effect. In the second part of the thesis, we study the magnetization dynamics in macroscopic systems that require a spatial dependence of the magnetic moment. We generate and control the dynamic states of the magnetic domains with oscillating fields, in the case of magnetic vortices, and with electrical currents, in the case of droplet solitons.
Download or read book Nonlinear Magnetization Dynamics in Nanosystems written by Isaak D. Mayergoyz and published by Elsevier. This book was released on 2009-04-20 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: As data transfer rates increase within the magnetic recording industry, improvements in device performance and reliability crucially depend on the thorough understanding of nonlinear magnetization dynamics at a sub-nanoscale level. This book offers a modern, stimulating approach to the subject of nonlinear magnetization dynamics by discussing important aspects such as the Landau-Lifshitz-Gilbert (LLG) equation, analytical solutions, and the connection between the general topological and structural aspects of dynamics. An advanced reference for the study and understanding of nonlinear magnetization dynamics, it addresses situations such as the understanding of spin dynamics in short time scales and device performance and reliability in magnetic recording. Topics covered include nonlinear magnetization dynamics and the Landau-Lifshitz-Gilbert equation, nonlinear dynamical systems, spin waves, ferromagnetic resonance and pulsed magnetization switching. The book explains how to derive exact analytical solutions for the complete nonlinear problem and emphasises the connection between the general topological and structural aspects of nonlinear magnetization dynamics and the discretization schemes better suited to its numerical study. It is an exceptional research tool providing an advanced understanding of the study of magnetization dynamics in situations of fundamental and technological interest.
Download or read book Linear and Nonlinear Magnetization Dynamics in Thin Ferromagnetic Films and Nanostructures written by and published by . This book was released on 2014 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonlinear Magnetic Damping and Parametric Excitation of Magnetization in Nanomagnets written by Han Kyu Lee and published by . This book was released on 2017 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the study of magnetization dynamics in a ferromagnetic thin film and nanoscale ferromagnets. In bulk ferromagnets, nonlinear interactions generally couple each spin wave eigenmode to a continuum of other available modes through multi-magnon scattering. The multi-magnon scattering can potentially limit an achievable amplitude of spin wave modes by pumping energy into other energy-degenerate modes. For example, two-magnon scattering process in the presence of impurities and defects is known to act as a channel of magnetic damping in ferromagnetic thin films. I present an observation of the two-magnon scattering in epitaxial La0.7Sr0.3MnO3 (LSMO) and LSMO/Pt thin films, investigate its impact on the evaluation of low magnetic damping in LSMO, and properties of spin transport through the LSMO/Pt interface for potential nanodevice applications.Magnetic damping is a critical parameter that determines the speed and energy efficiency of the magnetic nanodevice such as spin-torque memory and oscillators. In a nanomagnet, the geometric confinement breaks translational invariance of the system and discretizes the spin wave spectrum, which helps to suppress the kinematically allowed multi-magnon scattering. The suppression of multi-magnon scattering enables an unusual type of nonlinear interactions and excitation processes in nanoscale ferromagnets that are qualitatively different from that in bulk ferromagnets. In this regard, I report an observation of nonlinear resonant three-magnon scattering and its effect in the damping of nanoscale magnetic tunneling junctions (MTJs). The spectral lineshape of a spin wave resonance undergoing three-magnon scattering exhibits a minimum at the resonance frequency in sharp contrast to the amplitude maximum seen in the linear resonance regime. This unusual behavior arises because the damping parameter of a spin wave ceases to be frequency-independent and itself becomes a resonant function of the excitation frequency. Also, such resonant nonlinear damping dramatically alters the response of a nanomagnet to antidamping spin-torque in a counterintuitive way - the antidamping torque can increase the damping of a spin wave mode that undergoes the nonlinear resonant scattering.Lastly, I present an experimental demonstration of electric-field driven parametric excitation of a spin wave eigenmode in nanoscale MTJ. This work shows that the microwave electric field applied across the MTJ electrode efficiently couples to the out-of-plane component of oscillating magnetization via voltage-controlled magnetic anisotropy (VCMA) in the system. The threshold voltage of parametric excitation is found to be well below 1 Volt, which makes it attractive for magnonic nanodevices such as spin wave logic. The electric-field driven parametric excitation of magnetization is a versatile method for generating short-wavelength spin wave and thus results in this work pave the way towards energy-efficient excitation of magnetization dynamics in thin films of metallic ferromagnets and nanodevices based on magnetic multilayers.
Download or read book Static and Dynamic Magnetic Properties of Exchange Coupled Thin Film Systems written by and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Magnetism and Magnetic Materials written by Michael Coey and published by Springer. This book was released on 2021-11-19 with total page 1679 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook presents a comprehensive survey of magnetism and magnetic materials. The dramatic advances in information technology and electromagnetic engineering make it necessary to systematically review the approved key knowledge and summarize the state of the art in this vast field within one seminal reference work. The book thus delivers up-to-date and well-structured information on a wealth of topics encompassing all fundamental aspects of the underlying physics and materials science, as well as advanced experimental methodology and applications. It features coverage of the host of fascinating and complex phenomena that arise from the use of magnetic fields in e.g. chemistry and biology. Edited by two internationally renowned scholars and featuring authored chapters from leading experts in the field, Springer’s Handbook of Magnetism and Magnetic Materials is an invaluable source of essential reference information for a broad audience of students, researchers, and magnetism professionals.
Download or read book Atomistic Spin Dynamics written by Olle Eriksson and published by Oxford University Press. This book was released on 2017 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several large experimental facilities that focus on detection and probing magnetization dynamics have been realized in Europe, USA and Japan. This book covers theoretical and practical aspects of the vibrant and emerging research field of magnetization dynamics.
Download or read book Spin Waves written by Daniel D. Stancil and published by Springer Science & Business Media. This book was released on 2009-04-05 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book begins by introducing magnetism and discusses magnetic properties of materials, magnetic moments of atoms and ions, and the elements important to magnetism. It covers magnetic susceptibilities and electromagnetic waves in anisotropic dispersive media among other topics. There are problems at the end of each chapter, many of which serve to expand or explain the material in the text. The bibliographies for each chapter give an entry to the research literature.
Download or read book Magnetic Nanostructures written by Hari Singh Nalwa and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twelve contributions comprise a reference source that is a coherent presentation of the state of the art in this fast growing area of nanotechnology research. Magnetic nanostructures are important for their phenomenal potential for storage; their great commercial value will come from applications in
Download or read book Magnetism of Surfaces Interfaces and Nanoscale Materials written by Robert E. Camley and published by Elsevier. This book was released on 2015-10-27 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past 30 years, magnetic research has been dominated by the question of how surfaces and interfaces influence the magnetic and transport properties of nanostructures, thin films and multilayers. The research has been particularly important in the magnetic recording industry where the giant magnetoresistance effect led to a new generation of storage devices including hand-held memories such as those found in the ipod. More recently, transfer of spin angular momentum across interfaces has opened a new field for high frequency applications.This book gives a comprehensive view of research at the forefront of these fields. The frontier is expanding through dynamic exchange between theory and experiment. Contributions have been chosen to reflect this, giving the reader a unified overview of the topic. Addresses both theory and experiment that are vital for gaining an essential understanding of topics at the interface between magnetism and materials science Chapters written by experts provide great insights into complex material Discusses fundamental background material and state-of-the-art applications, serving as an indispensable guide for students and professionals at all levels of expertise Stresses interdisciplinary aspects of the field, including physics, chemistry, nanocharacterization, and materials science Combines basic materials with applications, thus widening the scope of the book and its readership
Download or read book JETP Letters written by and published by . This book was released on 1993 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ferromagnetic Resonance written by Dr. Orhan Yalçın and published by BoD – Books on Demand. This book was released on 2013-07-31 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book Ferromagnetic Resonance - Theory and Applications highlights recent advances at the interface between the science and technology of nanostructures (bilayer-multilayers, nanowires, spinel type nanoparticles, photonic crystal, etc.). The electromagnetic resonance techniques have become a central field of modern scientific and technical activity. The modern technical applications of ferromagnetic resonance are in spintronics, electronics, space navigation, remote-control equipment, radio engineering, electronic computers, maritime, electrical engineering, instrument-making and geophysical methods of prospecting.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Classical And Quantum Dynamics In Condensed Phase Simulations Proceedings Of The International School Of Physics written by Bruce J Berne and published by World Scientific. This book was released on 1998-06-17 with total page 881 pages. Available in PDF, EPUB and Kindle. Book excerpt: The school held at Villa Marigola, Lerici, Italy, in July 1997 was very much an educational experiment aimed not just at teaching a new generation of students the latest developments in computer simulation methods and theory, but also at bringing together researchers from the condensed matter computer simulation community, the biophysical chemistry community and the quantum dynamics community to confront the shared problem: the development of methods to treat the dynamics of quantum condensed phase systems.This volume collects the lectures delivered there. Due to the focus of the school, the contributions divide along natural lines into two broad groups: (1) the most sophisticated forms of the art of computer simulation, including biased phase space sampling schemes, methods which address the multiplicity of time scales in condensed phase problems, and static equilibrium methods for treating quantum systems; (2) the contributions on quantum dynamics, including methods for mixing quantum and classical dynamics in condensed phase simulations and methods capable of treating all degrees of freedom quantum-mechanically.
Download or read book Advances in Nanoscale Magnetism written by Bekir Aktas and published by Springer Science & Business Media. This book was released on 2008-09-08 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book aims to provide an overview of recent progress in the understanding of magnetic properties in nanoscale through recent results of various theoretical and experimental investigations. The papers describe a wide range of physical aspects.
